The invention relates to a brake system for motor vehicles, with an activating unit which consists of a pneumatic brake booster as well as a master brake cylinder which is connected at the outlet side to the same, and to which the wheel brakes are connected, whereby the control valve of the brake booster can be triggered, independently of the volition of the driver, by means of an electromagnet, by means of the armature of which one of the control valve sealing fitting units can be activated, with a brake pressure controller, to which is conveyed the standard difference between a signal corresponding to the nominal braking pressure and a signal corresponding to the actual braking pressure, which difference is formed in a first adding device and the output quantity of which, which corresponds to a nominal armature travel, is compared in a second adding device with a signal which corresponds to the actual armature travel, whereby the standard difference corresponding to the comparative result is conveyed to a position control unit which influences the position of the control valve, the output quantity of which corresponds to the electrical current which is to be supplied to the electromagnet.
Such a type of brake system is already known from international patent application WO 95/03196. The structure of the previously-known brake pressure controller represents a compromise between the control unit dynamic which is desired and the disturbance behavior of the control unit. If a highly dynamic or very rapidly operating control unit is used, then this has a gradated characteristic curve, which has noises and vibrations in the system, which act in an unpleasant manner, as its consequence.
In the case of a slowly operating control unit, greater imprecisions in changing operations (changes in the operational sign or of the direction) in regard to the nominal value must then be accepted in return.
It is thus the object of the present invention to propose measures which make possible a control with the following characteristics:
a) For the sequence control:
C High dynamics; PA1 C Smooth, continuously adjustable control process; PA1 C Rapid response behavior. PA1 C Rapid stabilization of disturbances; PA1 C No permanent standard deviation.
b) For disruption behavior, static control inputs, or final value control: